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Clean Power Signs Steam and Heat Recovery Engine Development Agreement With Voith Turbo GmbH & Co. KG

Basic components of the CESAR system. Click to enlarge.

Canada-based Clean Power Technologies Inc. (CPT), developer of a waste-heat powered steam hybrid system (CESAR, Clean Energy Storage and Recovery, earlier post), has signed a collaboration agreement with Voith Turbo GmbH & Co. KG to develop steam and heat energy recovery engines for Clean Power’s proprietary heat recovery technology for refrigeration trailers for the grocery market.

CESAR uses a heat exchanger to capture waste energy from a primary engine, which is then stored in the form of steam in an accumulator, for on-demand use either in the same primary engine, or in a secondary vapor engine. Power can be produced solely by the secondary vapor engine even after the primary combustion engine has shut down. The technology can provide up to 40% better fuel efficiency and a corresponding reduction in emission levels depending upon the application, according to the company.

Under the terms of the collaboration agreement, Clean Power and Voith will analyze data from the testing of an existing refrigeration engine, results from which will be used to build and test a new engine that incorporates Clean Power’s heat recovery technology. Clean Power is currently collecting initial data from an existing refrigeration engine at its headquarters in Calgary, Canada.

There are more than 7 million refrigerated trailers in the US and about 2.5 million in the EU. The UK alone has approximately 40,000 refrigerated trailers while the overall global truck market is growing at 8% per year.

Voith is a multi-national company with significant interest in the development of expand in engine and braking systems. As part of its own drive systems and components development program, Voith Turbo GmbH & Co. KG has already developed hybrid systems, waste recovery systems and expansion engines based on the internal combustion engine which are used on the road, on rail, on water and in other industries.

Earlier in August, CPT signed a Memorandum of Understanding with East West Express Inc., a trans-Canadian freight trucking company, to work together with the ultimate objective of making the East West truck fleet more energy-efficient by installing the CESAR system to generate steam power for both motive and auxiliary power. Under the terms of the MOU, East West will provide Clean Power a Road Load Data Collection Vehicle. From this data Clean Power will refine the design and packaging of its exhaust heat capture, accumulator and steam engine to ensure that, together, they meet or exceed the specifications of the existing diesel engine system.

In 2006, CPT began testing the CESAR on a Mazda RX8 passenger vehicle engine, with trials on a second identical engine commencing later that year. The RX8 uses a twin-chamber Wankel rotary engine. In the CPT tests, one chamber is powered by gasoline, the other can be powered either by steam or by gasoline. In June 2007 testing also began on a Caterpillar C15 diesel engine to explore applications, such as auxiliary power and trailer refrigeration, within the industrial vehicle and truck industries. Testing on the CESAR process began in late October 2007.



I have to laugh at some of the claims some of these companies make. 40% fuel economy improvement? Boy I'm sure BMW would love the have those kinds of gains with their own TurboSteamer technology, which is schematically similar. Only the latter gives more sober (and believable) results: on an idealised basis, BMW claims a 3.7 percentage point improvement in brake thermal efficiency using a water-based Rankine-Clausius cycle heated from exhaust, and this can possibly be extended by a further 2 percentage points if coolant enthalpy is recovered in a separate ethanol vapourising- and expanding cycle. Taken together, therefore, if a 5 percentage point BTE improvement is assumed, the relative improvement in brake thermal efficiency on an ICE with a best point efficiency of 40% amounts to about 12%. Even if you halve that figure and assume the same boost from heat recovery, it's still only a 25% relative improvement, well short of the 40% claim in the above.

But don't believe what I say, read MTZ May 2008, pp. 20-27.

Henry Gibson

This is a recreation of the old Still cycle with a modern name. It can be highly efficient as demonstrated by the combined cycle gas-turbine-steam-turbine combination. It was used many places including the Kitson-Still locomotive that used 1/8 the weight of diesel as coal used in steam-locomotives at that time. If the California railroads has invented a Kitson-Still locomotive in 1926, they would yet be using them for their cheap construction, cheap maintenance and their efficiency. California railroads used oil to power most of their their steam locomotives not coal.

Semi-trailers have enough space to accomodate the boilers and condensers needed for such a system. ..HG..

Henry; do you have a reference site for Kiston_Still, or similar technology(that is relatively unbiased)-would be interesting to see. Richard

Roger Pham

A HDV diesel has peak thermal efficiency of ~42% and up to 45% with turbocompounding. 30% of heat energy is lost via exhaust, 18% via coolant and ~5-10% via turbocharger intercooler, and the rest is via other parasite losses. Given the temperature of the exhaust heat, a Doble steam car in the 30% can get about 25% efficiency via single stage expansion uniflow piston-cylinder. 25% of 30% exhaust heat will give you about ~8% gain in thermal efficiency. So, the combine-cycle diesel-steam rankine will net about 50% thermal efficiency, or a 19% improvement in mpg at steady cruise.

However, due to the steam storage capability allowing the engine to be shut off during downhill, slow speed or idling wherein the diesel's BTE is real low, one may see a combined improvement in mpg in the order of 30-40%, depending on the driving mode. However, the risk of boiler explosion has to be contained, so to speak!


You mean Thomas the steam engine will be coming back as hybrid trains in the near future? That would be neat!

Roger; when you use the term "turbocompounding", is this meant to be something more than the use of a turbocharger, which is used in nearly all heavy duty diesels now? Richard


Why has no one considered using absorption refrigration for all these refrigrated trucks using the exhaust heat?


"steam engine will be coming back"
That will not be bad idea at all.
look on the link below.
But that contemperary solution.

Let see what else can be done.
The only way to improve thermal efficiency of contemporary internal and external combustion engine is to re-think the pressure to work conversion. If the pressure can be converted to velocity and then converted to useful work then we stocking of thermal efficiency of 85% (water turbine have mechanical efficiency around that if I am correct).
In order to do the conversion you have to re-direct the random movement of molecules of hot medium to systematic unidirectional movement.

The only way to do that with out loosing significant amount of energy is to used the analogy of vortex cone. The shape convert the random movement in to linear. That how tornado work. This process is very efficient.


Heat rejection of a HDV diesel can be increased through the ceramic coating of the combustion chamber and exhaust mains. I'll find a PDF from the JPL and post a link to it...


Heat rejection of a HDV diesel can be increased through the ceramic coating of the combustion chamber and exhaust mains. I'll find a PDF from the JPL and post a link to it...


"Roger; when you use the term "turbocompounding", is this meant to be something more than the use of a turbocharger, which is used in nearly all heavy duty diesels now? Richard"


The regional diesel engine reco people have an exhaust manifold ceramic coating service, (not sure if they also spray the cylinder head) but surely they would if they could.
The practical result from maintaining heat in the manifold is improved gas flow for turbocharger. and cooler under hood temps.
If they can increase chamber temperature/ without cooking the metal, then higher temperature combustion results in more complete burning.
Ultimately ceramic / coated pistons etc will take this further. Although I am unaware of successful or mass production.
The other side of heat rejection in a conventional sense is that the chamber is cooler prior to combustion.
As the work done is a factor of the lowest temp to the highest temp achieved, this is a very real way to extract more energy from combustion.
If we take the 18% thermal losses to radiator supplied by Roger P, then the ceramic will also cut that number significantly.
The ceramic reflects the heat back into the chamber allowing high temp without destruction. (while it lasts)

I know this is not what you were asking, but Interesting and on topic sort of in that this heat recovery wants the waste heat currently going to the radiator/ water jacket.



As I understand it, ceramic coating of the cylinder head has essentially no impact on combustion temperatures. Ideally, heat rejection would be high enough to do away with the water jacket altogether: engine temps would be regulated by the temperature of combustion and intake events. Doubt current engines would last very long at ~500f...

Excellent idea that they had about running a Crower cycle in a rotary. Too bad the wankel suffers from sealing issues.


A large hybrid diesel long haul truck with turbo compounding and heat recovery could save quite a bit of fuel. If they get 4 mpg fully loaded, getting 5-6 mpg would make a big difference in fuel consumption and costs to the owner.

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